The dust, planetesimals and planets of HD 38529

TL;DR

This study investigates the dust and planetesimal distribution around the star HD 38529, combining observational data and dynamical modeling to identify dust-producing regions and compare them to our Solar System's structure.

Contribution

It provides the first detailed dynamical and spectral energy distribution analysis of dust and planetesimals in the HD 38529 system, identifying stable dust-producing regions and their potential similarities to the Solar System.

Findings

Dust emission primarily originates from 20-50 AU region.

Stable niches for planetesimals are identified at 0.4-0.8 AU, 20-50 AU, and beyond 60 AU.

Upper limits on dust mass in the inner region are established.

Abstract

HD 38529 is a post-main sequence G8III/IV star (3.5 Gyr old) with a planetary system consisting of at least two planets having Msin(i) of 0.8 MJup and 12.2 MJup, semimajor axes of 0.13 AU and 3.74 AU, and eccentricities of 0.25 and 0.35, respectively. Spitzer observations show that HD 38529 has an excess emission above the stellar photosphere, with a signal-to-noise ratio (S/N) at 70 micron of 4.7, a small excess at 33 micron (S/N=2.6) and no excess <30 micron. We discuss the distribution of the potential dust-producing planetesimals from the study of the dynamical perturbations of the two known planets, considering in particular the effect of secular resonances. We identify three dynamically stable niches at 0.4-0.8 AU, 20-50 AU and beyond 60 AU. We model the spectral energy distribution of HD 38529 to find out which of these niches show signs of harboring dust-producing plantesimals. The secular analysis, together with the SED modeling resuls, suggest that the planetesimals responsible for most of the dust emission are likely located within 20-50 AU, a configuration that resembles that of the Jovian planets + Kuiper Belt in our Solar System. Finally, we place upper limits (8E-6 lunar masses of 10 micron particles) to the amount of dust that could be located in the dynamically stable region that exists between the two planets (0.25--0.75 AU).